Method and apparatus for oral hygiene



Jan. 4, 1966 J, w. MATTINGLY 3,227,158

METHOD AND APPARATUS FOR ORAL HYGIENE Filed May 8, 1961 3 Sheets-Sheet 1 I. FREQUENCY PR SURE PULSE JET 2 Es CHARACTERISTICS KINETIC, ENERGY VOLUME SHAPE OF MASS MECHANICAL FAcToRs s I II 4 ECT ON I TOTAL VALUE" 5. TIssuE 0F ELASTIC TONE REBOUND ABILITY SE T e. TISSUE CAPILLARY RELATED TO FREQUENCY AND STAGNATION DEPTH OF MANIPULATION HUMAN FACTORS 7. TISSUE NERVE RELATED TO RESPONSE THRESHOLD OF PAIN 0 1 I g l U- 0+- 2 4"- 0 I000 I600 5 g FREQUENCY cycles Per- Minute I I g o 2 LL! 0! a: :32 I a TIME L O 1: 9- 0! Q: E V I0 INVEN TOR.

0 John W. Mafflngly TIME A TTORNE YS Jan. 4, 1966 J. w. MATTINGLY METHOD AND APPARATUS FOR ORAL HYGIENE 3 Sheets-Sheet 2 Filed May 8, 1961 INVENTOR. John W Matting y BY Wfigwi m ATTORNEYS Jan. 4, 1966 J. w. MATTINGLY 3,

METHOD AND APPARATUS FOR ORAL HYGIENE Filed May 8, 1961 5 Sheets-Sheet 5 V INVENTOR.

' g 10 John W. Muff/n9 y BYG if ATTORNEYS United States Patent METHOD AND APPARATUS FOR ORAL HYGIENE John W. Mattingly, Fort Collins, Colo., assignor to Aqua- This invention relates to the use of high velocity liquid jets in the practice of oral hygiene and particularly to an improved method and apparatus for affording greater effectiveness of liquid jets for stimulating the gum tissues and in the cleaning of teeth and adjacent tissues.

One of the continuing problems in the field of oral hygiene is that of providing simple and effective methods for assuring cleaning of teeth and stimulating the circulation of blood in the adjacent tissues. One of the methods which has met with some degree of success employs a high velocity jet of liquid which may be directed against the teeth and into the spaces between the teeth and the gums. Difficulties have been encountered in securing adequate and sustained liquid pressure and in providing simple and easily manipulated apparatus for nontechnical users. Ac: cordingly, it is an object of this invention to provide an improved method for applying a jet of liquid for cleaning the teeth, subgingival margins, and interproximal spaces.

It is another object of this invention to provide an im: proved method for cleaning teeth and for stimulating the tissues about the teeth.

It is another object of this invention to provide an improved apparatus for use in oral hygiene to produce a high velocity liquid jet for cleaning vpurposes.

It is a further object of this invention to provide an improved liquid jet apparatus for use in oral hygiene which efiects both cleaning of the teeth surfaces and tissue stimulation.

Briefly, in carrying out the method of thisinvention in accordance with one procedure. thereof, a fine high velocity jet of liquid is produced and is caused to pulsate at a useful not only in daily cleaning but also for stimulating the circulation of blood in the gum tissues and improving the elastic tone of the gum tissue through massage or artificial exercise in connection with the treatment of discases of the teeth and gums.

One form of apparatus for facilitating the practice of this method is constructed to include a reciprocating pump I and a reciprocating plunger arranged in a body of liquid to produce a jet pulsating at the required rate. Thepump is provided with controls to eliect adjustment of the volume and pressure or intensity of the jet and a convenient liquid supply is provided tofacilitate the use of any desired cleansing liquid or solution.

The features of novelty which characterize this inven tion are pointed out in the claims appended to and forminga part of this specification. The invention itself, however, both as to its organization and method of operation may best be understood upon reference to the accompanying drawings, in which:

FIG. 1 is a chart indicating the relationship of the principal factors a fecting the evaluation of a pulsed jet for oral hygiene;

FIG. 2 is a graph illustrating the value characteristics of a pulsed jet with a range of frequencies;

FIG. 3 is a perspective view of a jet type oral hygiene apparatus embodying the invention;

FIG. 4 is an enlarged detail elevation view of the intake and bypass fixture of the apparatus of FIG. 3

FIG. 5 is a front elevation view partly in section of the motor-pump unit of the apparatus shown in FIG. 3;

FIG. 6 is a side elevation view partly in section of the device taken along the line 66 of FIG. 5;

FIG. 7 is a sectional plan view of the pump of the device taken along the line 77 of FIG. 6;

FIGS. 8 and 9 are graphs illustrating certain operating characteristics of the apparatus of FIG. 2;

FIG. 10 is a sectional view of the nozzle assembly of the apparatus of FIG. 2; and

FIG. 11 is a sectional plan view of another form of pump suitable for use in practicing the method of this invention.

Extensive studies of the characteristics of water jet devices for oral hygiene were made in connection with this invention. In the course of these studies, the dimensions of the jet as well as its pressure, volume and fre: quency characteristics were investigated. Further, it was found that the efiectiveness of the liquid jet depends upon the characteristics of the individual gum tissue, these characteristics for a wide range of gum tissue conditions were studied and evaluated. Liquid jet devices embodying the invention were employed to determine the effectiveness of the liquid jet under varying conditions of opera tion and for various adjusted conditions of the device. The characteristics of the gum tissue studied involved the elastic tone of the tissue, the nerve response and capillary stagnation which is a condition of swelling brought about by stagnation of blood in the region of capillary transfer from artery to vein.

Initially the optimum size of the jet orifice was investigated and found to lie generally within the range of .025 inch to .045 inch in diameter, these being eifeotively the outside limits of a practical form of the device as tested. A jet of the order of .025 inch or smaller results in a reaction when directed against the gum tissue which is somewhat similar to the effect of prodding with a pointed instrument even in tissues of high elastic tone. When the orifice size is increased to over .045 inch in diameter, the jet size is'excessive in proportion to the masses of gun tissue which must be manipulated in the average oral structure. These larger size jets are also of excessive size when considered from the standpoint of probing, flushing and cleaning the tooth surfaces and zones between teeth, and in addition'the larger jets discharge at an uncomfortably large or inconvenient rate of flow of water or other fluid and render the device more difficult to use. The optimum size for the orifice, determinative of the discrete areas of contact of the pulse with gum tissue, was found to lie within a range of the order of .032 to .038 inch.

The desirable discharge pressure ranges were studied and 'it was found that normal gum tissue could tolerate a steady flow discharge at pressures of the order of pounds per square inch provided short rest periods were allowed. From these studies it appeared that the pressures to be employed should be maintained at or below a maximum design pressure of 90 pounds per square inch and it was further determined that pressures Within this range were adequate for cleaning purposes whereas higher pressures might result in some cases in damage to gum tissue and the more sensitive and fragile sub-lingual tissue.

After determination of the desired size and pressure ranges, the human factors were analyzed and the elfect of various flow conditions was investigated. It is, of course, desirable to maintain the characteristics of the jet such that the use of the instrument will not result in pain. This being a variable factor, the device may be adjusted to provide conditions suitable for the individual applications. The elastic tone of the gum tissue is important and determines-to a substantial degree the desired characteristics of the jet stream. The kinetic energy delivered to-discrete areas of the gum tissue must be sufiiciently great to cause a desirable depth of depression of the tissue for purposes of manipulation and stimulation, and the pulses must be of a frequency such that time is allowed for the tissue to rebound when the jet is directed against it to cause depression to the desired depth. In the course of the investigation it was found that certain patients experienced pain at frequencies of the order of 1750 cycles per minute when the elastic tone of the gum tissue was low and the tissue was swollen. Investigations using a stroboscope showed that tissue of good average tone failed to rebound completely when treated at frequencies as high as 1750 cycles per minute. On the other hand, tissue of lower elasticity was observed to rebound fully at frequencies of the order of 1250 cycles per minute and no tendency toward painful reaction was observed at these frequencies. Frequencies of the order of 1250 cycles per minute also produced highly satisfactory reaction of tissue having good elastic tone.

For some tissues of low elastic tone relatively low frequencies were found to be usable; however, such frequencies, of the order of say 800 cycles per minute, do not produce an adequate stimulation reaction on tissue of high elastic tone.

All of the factors taken into consideration during the investigations were analyzed and weighed in terms of a total or effective value of the pulse jet. The term total value may be defined as a characteristic of the jet within predetermined ranges of size and pressure related to the ability of gum tissue to respond in a beneficial manner to impingement of the jet pulses.

Referring now to the drawings, FIG. 1 is a chart illustrating the relationship of the seven principal factors which are involved in determining the total value of a pulse jet under investigation. The first four factors-frequency, pressure, volume and sectionrelate to the physical dimensions and characteristics of the jet and have been designated mechanical factors. The last three factorselastic tone, capillary stagnation, and nerve response-relate to properties or characteristics of the tissue and have been designated human factors. The elastic tone determines the rebound ability of the gum tissue and to this extent has been designated a mechanical factor as well as a human factor.

The Total value of a pulse jet is illustrated graphically in FIG. 2, which is a curve representing the variations of total value of the jet for a wide range of pulse frequencies. As illustrated on this curve, the total value rises to a peak at approximately 1250 cycles per minute and is relatively high over a range of about 1000 to 1600 cycles per minute, falling off rapidly outside this range. The range of 1200 to 1400 cycles per minute was determined to be quite flat and represents the optimum range of pulse frequencies.

Referring again to the drawings, the apparatus illustrated in FIG. 3 comprises a motor-pump assembly provided with a flexible intake conduit 11 and a flexible discharge conduit 12. A jet nozzle 13 is secured to the conduit 12 by a coupling 14 and may easily be manipulated to direct a high volocity jet produced at the nozzle 13 against the teeth and the gum tissue. The pump unit 10 is provided with an adjusting knob 15 which controls a bypass from the discharge side of the pump to a fiexible conduit 16. The conduit 16 is made of a resilient flexible material which expands upon application of internal fluid pressure and provides a damping action referred to below. The conduit 12, on the other hand, is

made of relatively inexpansible flexible material to minimize damping action in the discharge line. The ends of the conduits 11 and 16 are attached to a fitting 17, which may be placed in a cup or other liquid container as indicated at 9. The fitting 17, shown in detail in FIG. 4, includes two coupling sleeves 18 and 19 of molded plastic material, over which the ends of the conduits 11 and 16, respectively, are secured. The sleeves are made integrally with a yoke 20 which extends below the ends of the sleeves and spaces the ends from the surface on which the fitting rests. The sleeve 18 has its lower end open, as indicated at 21, and when the fitting rests within a liquid container, the yoke 20 holds the open end spaced from the bottom of the container and allows liquid to enter the opening freely. The sleeve 19 is closed at its lower end and is provided with a restricted opening 23 which limits the discharge of liquid through the bypass tube 16.

The motor pump unit shown in FIGS. 5, 6 and 7 has a casing 26 which in the form illustrated comprises a die casting having a bottom wall 27 and a top Wall 28, the top wall being stepped as indicated at 29 in FIGS. 3 and 5. The stepped portions 29 are connected to the bottom wall by side walls 30. Between the side walls 30 there are provided inwardly extending wall portions 31 and forwardly extending walls or panels 32. The sides of the walls 30 are sloped as indicated at 33 and the space between the walls 32 is closed at its rear by an end wall 34 having a forwardly extending flange portion 35 near the lower end thereof and spaced from the bottom wall 27. The forward side of the space is closed by a removable front plate 32a held in place by two screws 35a threaded into the wall portion 35. A motor control switch 24 is mounted in the casing 26 below the top wall 28 and may be operated by a knob 25 mounted on top of the casing where it is easily accessible and convenient to the operator.

A motor pump or housing unit 37 is mounted on top of the walls 32 and has a cylinder portion 38 extending downwardly between the walls. The pump unit 37 is rounded along its sides and one side portion fits a complementary rounded wall section 39 connecting the forward edges of the walls 28 and 34. An electric motor 41 is mounted within the main compartment of the easing and is secured by screws or bolts 42 to the inwardly extending wall portions 31, and the rear end of the casing is closed by a plate 43 secured in place by screws 44 fitting through tubes or posts 45 and threaded into the wall portions 31 as indicated at 46. The motor has been illustrated somewhat diagrammatically as its details of construction are not essential to an understanding of the invention.

The motor is provided with a shaft 48 extending both forwardly and rearwardly therefrom, the rear portion of the shaft carrying a motor cooling fan 49 for circulating air through the casing from a circular opening 51 in the plate 43 over the motor and through the casing and thence downwardly and out through a passage 52 formed between the bottom wall 27 and flange 35 and the two side walls 32.

The pump 37 is of the reciprocating type and includes a plunger 54 mounted on a rod 55 and driven by a Scotch yoke mechanism including a yoke 56 mounted on and secured to the rod 55 by a set screw 59 and having a cross slot or guide 57 in which a roller or roller hearing 53 can move or ride. The roller 58 is carried on a stub shaft 60 mounted in a gear 61 having a shaft 62 secured in the wall 34; the roller 58 then moves back and forth in the slot 57 and reciprocates the rod 55 when the gear 61 is rotated, thus providing forward and reverse strokes occurring during each respective half revolution of the driving roller 58 as it is rotated through a complete revolution by shaft 62. The gear 61 is driven by a pinion gear 63 mounted on the shaft 48 of the motor, the shaft and pinion extending through the wall 34 in a circular opening 64. The lower end of the rod 55 passes through a guide opening 66 provided in the wall portion 35.

The pump assembly 37 may be constructed of molded plastic or other suitable material and the cylinder portion 38 of the pump housing comprises a piston block formed to provide a cylinder 67 within which the piston 54 is mounted for sliding movement andsealed by suitable means such as an O-ring 68 mounted in an annular groove in the cylinder wall. The piston block is cemented or otherwise suitably secured to a main head portion 70 and the pump casing is completed by a closure portion 71 cemented or otherwise suitably secured to the portion 70. A mounting flange 72 depending from the portion 70 is attached to the wall 34 by screws 73 and holds the pump assembly securely in position on the housing.

As shown in FIG. 7, the pump casing portions 70 and 71 cooperate to form a chamber 74 having aninlet valve 75 for controlling an inlet passage 76 and an outlet valve 77 for controlling an outlet passage 78. The outlet passage 78 is formed within a partition member 79 cemented to the closure portion 71 and providing an outlet chamber 81 in which the discharge valve77 operates. The

inlet valve 75 is provided with astem 82 and is mounted for reciprocation in a cylindricalrecess 83 in the partition 79. The discharge valve 77 is provided with a stem 84 mounted for reciprocation in a cylindrical recess 85 in the closure portion 71. Both valves are spring biased to their closed positions.

When the piston 54 is reciprocated by operation of the motor through the Scotch yoke mechanism, it is moved alternately in and out of the chamber 74 and when moving outwardly, during 180 rotation of drive shaft 62, draws liquid in through the passage 76 past the valve 75 and on the inward stroke, during the remaining half revolution, the valve 75 is closed and liquid is forced out through the port 78 on opening of the valve 77. It Will be understood that the flexible intake 1136.11 is secured in communication with the inlet conduit 76 by being slipped over a nipple 86 and that the discharge tube 12 is secured in connection with the outlet passage 78 and chamber 81 by connecting it over a nipple 87.

In order to control the rate and intensity or kinetic energy of discharge of liquid from the pump chamber 74 through the port 78, a bypass port 88 is provided and is arranged to be controlled by a needle valve 89 which may be moved toward and away from the port 88 by turning the adjusting knob 15. The shaft of the knob 15 which carries the valve 89 is threaded in a bushing 91, and a spring pressed seal 92 is provided to prevent leakage through the bushing.

During the operation of the pump the liquid is discharged with pulsations at a rate determined by the speed of the pump and the force of the discharge is controlled by the position of the valve 89, it being greatest when the valve 89 is in its position to close the port 88 and less as the valve is moved away from the port. The motor speed is selected for reasons discussed above so that the rate of pulsations lies within the range of 1000 to 1600 cycles per minute; and in a preferred embodiment, the motor speed is such that the piston 54 is driven at a rate of the order of 1300 cycles per minute. It will be understood that the ratio of the gears 61 and 63 is selected to provide the desired speed depending upon the normal speed of the motor 41. In some instances it may be desirable to provide a speed control for the motor in order to adjust the frequency of the jet pulsations within the required range. Controls for adjusting motor speeds are well understood in the art of motor control and a speed control has not been illustrated as it is not essential to an understanding of the present invention.

By stroboscopic observation of the jet stream discharged from a pump embodying the invention, it was determined that separate pulses. of water were produced and that after each pulse the water can be observed to withdraw a short distance within the orifice. Observations were made with an oscilloscope and strain gauges and it was found that when the bypass is closed and the pulse is discharged at full pressure the curve started at zero pressure and peaked at approximately pounds per square inch, by way of example, in one unit which was tested. The discharge in this unit was at a frequency of approximately 1150 cycles per minute, the stroke of the piston was "V inch and the orifice was .038 inch in diameter.

The wave form of this jet as discharged is illustrated in the graph FIG. 8. On this diagram the point A is at the beginning of the exhaust stroke of the pump. The sharpness of the curve at this point indicates that there is a shock characteristic. The hump at B is caused by surges in the system due to the valve action. The sharpness of the discharge curve at A as indicated results in a shock characteristic and this facilitates the stimulation of tissue of good elastic tone when maximum stimulation is desired.

Whenit is desired to reduce the shock effect, the valve 89 is opened to bypass a portion of the liquid and to introduce a damping effect due to expansion of the walls of the conduit 16 and, by way of example, a resulting pressure curve is indicated in FIG. 9. Here it will be noted that the maximum pressure has fallen from 90 pounds to 80 pounds per square inch and that minimum pressure of 10 pounds is present during operation. The Wave form is smooth, the shock characteristic having been removed.

-It is thus apparent that a change in characteristic of the pulsed jet may be effectively secured by employing the bypass arrangement or other control for adjusting the intensity of the jet.

In order that the nozzle 13 may be changed (for example, so that several members of the family may use the device), the coupling 14 is constructed as shown in FIG. 10. A flitting or sleeve 93 is provided with a recess or socket 94 at its left end to receive the end of the flexible tube 12 and near its right end has an O-ring of synthetic rubber or other suitable plastic positioned as indicated at 95 in an internal annular groove. The nozzle 13 is mounted on a base 96 which includes a plug member 97 which may be inserted into the fitting 93 so that an annular groove 98 at the end of the plug is engaged by the O-ring 95 and retained in position. The O-ring seals the coupling and also affords rotation of the nozzle 13 with respect to the fitting 93.

During use of the device the supply fitting 17 is placed in the bottom of the receptacle or glass 9 and the pump started by energizing the motor 41. When it is desired to use the nozzle 13, the force of the discharged jet is adjusted by movement of the knob 15 and the jet is then directed against the gums and into the spaces between the tooth areas. The pulsating characteristic of the discharged jet of liquid stimulates the circulation of blood in the gum tissue and also dislodges particles of matter caught between the teeth. The nozzle may be turned to select the most desirable angle for directing the jet. In most instances it; is preferable to place the nozzle in the mouth before starting the motor in order to prevent undesirable discharge of the jet about the room. When the nozzle is not in use it may be placed in a holder formed by a bar or a cleat I00 mounted in frictional engagement on the tubes 11 and 16 in spaced relationship to the pump body 37; the cleat having holes slightly smaller than the flexible tubes may be pressed on the tubes. The position of the nozzle when in this holder is indicated by dotted lines in FIG. 3.

Various other types of pumps may be employed to secure the desired pulsating jet effect, and another pump suitable for this purpose has been indicated in FIG. 11 which is a sectional plan view through a pump body of generally cylindrical configuration. The pump body indicated at 102 is provided with a cylindrical pump chamber 103 in which an eccentricallymounted rotor104 is mounted within a flexible belt or sling 105 and is driven from a shaft 106 on an eccentric stub shaft 106a so that the sling 105 is moved about the chamber 103. The direction of movement of the rotor 104 is indicated by the arrow, and as it moves from the position shown liquid is drawn in through an intake port 107 filling the space on the rearward side of the flexible sling 105 and at the same time moving liquid out of the forward side and discharging it through a port 108 into a chamber 109 and thence through to the discharge outlet 110. This provides a pulsating stream which may be controlled as to its intensity by adjustment of a knob 112 on which a needle valve 113 is mounted to control a bypass port 114. When employing the pump of FIG. 11 for the device shown in FIG. 3, the intake tube 11 is coupled to the inlet port 107, the discharge tube 12 to the port 110 and the bypass tube 16 to the port 114.

In the assembly of the device as illustrated in FIG. 3, the tubing 16 is preferably made of a material sufliciently flexible to afford some expansion when the pressure of the discharge is applied between the discharge port of the pump and the orifice 23 in the fitting 17. This expanding action effects damping of the discharge and smooths the operation of the pump so that the discharge from the chamber 74 is in effect working against the flexible Walls of the tube 16, and when the valve 89 is open there is less shock in the discharge through the flexible conduit 12. The walls of the flexible conduit 12 are relatively firm so that there is minimum expansion of these walls and thus the range of intensity of force applied by the pulsating jet may be varied from the direct discharge when the bypass port 88 is closed to a relatively mild intensity when the bypass is wide open as shown in FIG. 7. A short length of more flexible tubing, indicated at 115 in FIG. 3, may be employed to couple the tube 12 to the nipple 87. And a similar flexible piece 116 may be employed to connect the tube 12 to the nozzle assembly 14. These short lengths of flexible tubing 115 and 116 are made of readily or highly bendable material and facilitate movement of the nozzle with minimum interference due to the relatively stiff characteristic of the discharge conduit 12. The lengths are sufficiently short not to introduce significant damping effect and do not change the overall non-damping characteristic of the discharge line. The readily bendable characteristic introduced by the short lengths together with the rotary mounting of the nozzle in its assembly provides for easy universal movement of the nozzle tip.

It will thus be apparent that the motor-pump unit illustrated may be employed effectively in the practice of the method of this invention. The unit may easily be adjusted as to the intensity of the pulsating jet discharged by the pump by adjusting the knob 15, and the speed of the motor and gearing may be selected to bring the rate of pulsations within the desired range for effective use of the method of this invention.

While the invention has been described in connection with particular pump unit constructions, various other de vices and methods of practicing the invention will occur to those skilled in the art. Therefore, it is not desired that the invention be limited to the specific details illustrated and described and it is intended by the appended claims to cover all modifications which fall within the spirit and scope of the invention.

I claim:

1. In the art of oral hygiene, the method of cleaning the teeth and stimulating the gum tissues which comprises forming a high velocity jet of liquid having a small cross section, directing the jet against the surfaces to be treated, and including the step of producing pulsations of the jet at a rate affording depression of the gum tissue during each pulse and its substantially full rebound between pulses and sufliciently rapid to afford effective cleansing of the treated surfaces.

2. In the art of oral hygiene, the method of treating the gum tissues, which comprises generating a pulsating stream of liquid of small crosssectional area consisting of spaced pressure pulses which rise and fall between maximum and minimum values of pressure,

directing said pulsating stream of liquid upon and moving it along the gum tissues for manipulating changing discrete areas thereof by repetitively depressing discrete areas of gum tissue with intermediate rebound, said repetitive pressure pulses as they successively impinge upon said discrete areas of said gum tissue having kinetic energy sufficient in quantity and applied during that period of time which produces said depression of said gum tissue, said spaced pulses being characterized by spacings one from the other of duration which provides for said rebound of said gum tissue. 3. The method of claim 2 in which said pressure pulses are separated from one another whereby said stream is completely interrupted during the spaces between pulses. 4. The method of claim 2 in which said spaced pressure pulses are produced at a rate of from about 800 pulses per minute to about 1600 pulses per minute.

5. The method of claim 4 in which the pressure pulses and the spaces between the pressure pulses are of about the same duration.

6. In the art of oral hygiene, the method of treating the gum tissues, which comprises generating a pulsating stream of liquid of cross-sectional area corresponding with a diametrical range between about 0.025 inch to about 0.045 inch consisting of spaced pressure pulses occurring at the rate of from about 800 per minute to about 1600 per minute and which rise and fall between maximum and minimum values of pressure, and

directing said pulsating stream of liquid upon and moving it along the gum tissues for manipulating changing discrete areas thereof by repetitively depressing discrete areas of gum tissue with intermediate rebound,

said repetitive pressure pulses as they successively impinge upon said discrete areas of said gum tissue having kinetic energy sufiicient in quantity and applied during that period of time which produces said depression of said gum tissue, said spaced pulses being characterized by spacings one from the other of duration which provides for said rebound of said gum tissue.

7. The method of claim 6 in which said maximum values of pressure lie within a range having an upper limit of about pounds per square inch.

8. In the art of oral hygiene, the method of concurrently cleaning the teeth and treating the gum tissues, which comprises generating a pulsating stream of liquid of small crosssectional area consisting of spaced pressure pulses which rise and fall between maximum and minimum values of pressure,

directing said pulsating stream of liquid against the gum tissues for repetitively depressing discrete areas of gum tissue with intermediate rebound thereof to and from depths which stimulate circulation therethrough of blood, and

moving said pulsating stream of liquid along the teeth and gum tissues for treating changing discrete areas thereof,

said repetitive pressure pulses as they impinge upon said discrete areas of said gum tissue having kinetic energysufficient in quantity and applied during that perior of time which produces said depression of said gum tissue followed by rebound of said gum tissue before a further pressure pulse produces the next depression of said tissue thereby to stimulate said circulation of blood while cleaning said gum tissue and associated teeth.

'9. The method of claim 8 in which said cross-sectional area corresponds to a diametrical range between about 0.025 inch and about 0.045 inch, and wherein said maxi mum pressure lies Within a range having an upper limit of about 90 pounds per square inch.

10. A system of treating gum tissue by applying spaced pressure pulses of liquid to depress discrete areas of gum tissue with the spacing of said pulses one from the other of duration which provides for rebound time for said gum tissue, comprising generating means for generating said spaced pressure pulses of liquid at a rate of from about 800 per minute to about 1,600 per minute each of said duration to produce said depression of said gum tissue and with spacings between said pulses of duration to provide said rebound time for said gum tissue after said depression thereof,

said generating means having a liquid inlet and a liquid outlet, and

means connected to said liquid outlet for delivering said pulses to said gum tissue without substantial change of the shape, the magnitude or of the spacing of said pulses, said last-named means including a nozzle having an opening of small cross-sectional area corresponding With a diametrical range between about 0.025 inch to about 0.045 inch for limiting to discrete areas the gum tissue to which said pulses are applied for repetitive depression and rebound of such discrete areas. 11. The system of claim 10 in which said means for generating said pulsating stream of liquid is provided with means located between said liquid inlet and said liquid outlet for varying the kinetic energy of the pulses pro duced at said liquid outlet to vary the magnitude of the cyclic depression and rebound of the gum tissue.

12. The system of claim 10 in which said means for generating said pulsating stream of liquid comprises a pump having a piston reciprocable in a pump chamber provided with said inlet and with said outlet, and means between said inlet and said outletfor varying the kinetic energy of the pulses of the stream of liquid delivered by said nozzle to the gum tissue to vary the magnitude of cyclic depression and rebound of the gum tissue comprising an adjustable liquid outlet connection from which there may be discharged from said pump chamber a selected fractional part of the liquid prior to entry into said outlet.

References Cited by the Examiner UNITED STATES PATENTS 313,879 3/1885 Nagle 103-41 932,520 8/1909 Wadsworth 137-108 1,203,525 10/1916 Fuller 137-568 X 2,029,734 2/ 1936 Meitzler 128224 2,852,033 9/1958 Orser 137-108 2,912,976 11/1959 Grund 128-62 FOREIGN PATENTS 221,259 9/ 1924 Great Britain. 382,430 10/ 1932 Great Britain.

RICHARD A. GAUDET, Primary Examiner.

ROBERT J. HOFFMAN, JORDAN FRANKLIN,

Examiners. 

1. IN THE ART OF ORAL HYGIENE, THE METHOD OF CLEANING THE TEETH AND STIMULATING THE GUM TISSUES WHICH COMPRISES FORMING A HIGH VELOCITY JET OF LIQUID HAVING A SMALL CROSS SECTION, DIRECTING THE JET AGAINST THE SURFACE TO BE TREATED, AND INCLUDING THE STEP OF PRODUCING PULSATIONS OF THE JET AT A RATE AFFORDING DEPRESSION OF THE GUM TISSUE DURING EACH 